Work has begun to put stock fencing around two of the commons that make up Chailey Common Local Nature Reserve.
The commons will still be accessible to the public throughout the work and the fence will include gates and cattle grids to allow public access once it is complete.
The fence is being erected to allow grazing by sheep and cattle to restore this nationally important heathland habitat.
Some parts have been rendered inaccessible by invasive plants such as silver birch, bracken and gorse.
Grazing over these areas will help control these species.
In the first phase of the fencing project, due to be completed before the end of March, access points will be added to Lane End and Red House Commons.
The second phase is planned to start in September and will see fencing around Memorial, Pound and Romany Ridge Commons.
The fencing scheme is being funded by Natural England through the Countryside Stewardship Scheme and the Environmental Stewardship Scheme.
It comes after many years of consultation and planning on how to protect this rare habitat.